Rat multiple organ blocks: microsurgical technique of removal for ex vivo aerobic organ preservation using a fluorocarbon emulsion.

A multiple organ block (MOB) is composed of en bloc removed organs (heart, lungs, liver, pancreas, kidneys, and bowel), connected by the vascular system, of which blood circulation is maintained by the heart and oxygenation by the lungs under artificial ventilation. The aim of this study is the description of a surgical technique of MOB removal in the rat. Ninety-five MOBs were removed from Wistar rats. The rats were anesthetized, a tracheotomy was performed, and the cannula was connected to a pressure-regulated respirator. A colectomy was performed. Ureters, vena cava inferior, aorta, and bile duct were cannulated using an operative microscope. The vessels that joined the MOB to the carcass were tied or coagulated to make removal of the MOBs possible. Once removed, the MOBs were placed in a vaseline oil bath at 37 degrees C and the aorta and vena cava were connected to an accessory vascular circuit to stabilize arterious pressure. Success rate (ex vivo survival of more than 10 min) after the 30th attempt was 90% and after the 60th attempt was 95% (global success rate 82%). Ex vivo survival of MOBs at 37 degrees C ranged from 1 to 450 min. Rat MOBs allows us to study the normothermic preservation of all the organs susceptible of being transplanted in one single series of experiments. We showed that removal of rat MOBs is feasible. This microsurgical technique is codified. Rat MOBs are suitable if perfusion liquids are difficult to obtain or if a great number of experiments are required. As MOBs are composed of synergically functioning organs in the absence of striated muscle, bone, and nervous system, they also could be useful for physiologic and pharmacologic studies.

Aerobic preservation of organs using a new perflubron/lecithin emulsion stabilized by molecular dowels.

The purpose of the study reported here was to explore a new strategy for the aerobic preservation of transplants using stable concentrated fluorocarbon emulsions as an oxygen delivery system. Fluorocarbons (FCs) are synthetic molecules, chemically and biologically inert, with a high oxygen-dissolving capacity. As they do not mix with water, it is necessary to emulsify them for intra-vascular use. Perfluorooctyl bromide (or perflubron) can be emulsifled with egg-yolk phospholipid (EYP), a nontoxic emulsifiant. The recent adjunction of amphiphilic fluorocarbon-hydrocarbon diblock molecules allows the obtaining of stable emulsions. By contrast with hemoglobin, fluorocarbons release oxygen following Henry's linear law rather than Barcroft's sigmoid curve. Release of oxygen by the FCs is only slightly influenced by temperature, which is an advantage for the preservation of organs. We tested a new 90% w/v fluorocarbon stem emulsion (perflubron/EYL/F6H10) diluted to 36% w/v with a hydroelectrolytic solution containing albumin, on four multiple organ blocks (MOBs; heart-lungs, liver, pancreas, kidneys, small intestine) of rats (EMOBs). Five control MOBs were perfused with a 50% v/v mixture of rat-blood and Krebs solution (KBMOBs). The lungs were ventilated with a FiO2 = 100%. In all cases the survival of the MOBs was greater than 210 min, with stable hemodynamics and preserved hydroelectrolytic and acid-base balances. The levels of lactate, amylase, and CK of the EMOBs were inferior (P < 0.05) to those of the KBMOBs between the first and the second hour. The diuresis of the EMOBs was higher (P < 0.05) than that of the KBMOBs (5.65 +/- 1.76 vs 1.21 +/- 0.28 mg/min). The production of bile, and the AST and ALT levels, were not significantly different. The PaO2 of the EMOBs was higher (P < 0.01) than for the KBMOBs. In normothermy, the maintenance of an aerobic metabolism using the FC emulsion caused less damage to the organs. Aerobic preservation of organs using FC emulsions therefore appears to be an attractive alternative to the presently used cold ischemia.